The invention generally relates to commercial and consumer products related to venting and draining of containers, and more particularly relates to venting and draining of beverage makers for aerospace applications. The invention is specifically suitable for applications that typically handle fluids and depend on a mechanical or electrical means to ensure reliable venting of air into or out of a container, such as a tank assembly in the case of a beverage maker.
Air vent valves are typically used in aircraft beverage makers in conjunction with filling and draining a fresh water tank assembly, but in the past such air vent valves frequently have not been as reliable as desired to meet stringent quality standards. While a number of variations of air vent valve systems currently exist, they are all primarily of the float type. In these devices, a plastic or metal float is pushed up by liquid filling a tank to shut a vent hole during a filling operation, and conversely the float drops away from the vent hole to open up the vent during drainage of the liquid from the tank. These floats are susceptible to wear and tear (typically pitting due to mechanical pounding particularly compounded by chattering and cracking) which then results in a leak, because the body surface of the float is no longer smooth enough to seat properly against the vent hole.
Floats may also not be able to seal properly due to wear and tear of the seat against which the float seals, because of high impact to the valve seat after some usage, from a variety of factors. This causes leaks which, depending on the galley configuration, can be sufficient to cause a wet carpet condition in the aircraft, which is clearly not desirable. Also, a float can at times become stuck in a seated position in an air vent valve, which prevents drainage of liquid from the beverage maker, resulting in an inoperative condition. A common complaint from the customers is that such beverage makers for aerospace application become inoperative due to failure of an air vent valve, since having a beverage maker out of service due to a relatively inexpensive component is very expensive for an airline. Another major disadvantage of some conventional air vent valves is that the valves can vibrate or chatter in an audible manner in the operating pressure range of the tank on an aircraft. This chatter is not only annoying, but is usually also sufficiently prolonged to cause continuous leaks during that time. The chattering and vibration shortens useful life of the vent valve, lowering customer satisfaction and causing higher warranty costs.
One prior known design for an aircraft air vent valve for a water reservoir includes a vent valve body having a vent outlet and a valve adapter having a fluid inlet that sealingly mate together to form a common interior flow chamber including a tubular collar, a spherical ball float constrained for longitudinal movement within the tubular collar, and a planar valve seat member with a central flow aperture is disposed within the vent valve body between the tubular collar and the outflow passage of the vent valve body. However, it has been found that such an air vent valve typically can cause a malfunction as the water reservoir reaches full capacity, by allowing the ball float to initially bounce off the planar valve seat member, which allows water to escape past the ball float and out the vent outlet. The initial bounce of the ball float typically also creates an oscillation of the ball float that can last indefinitely, allowing water to forcefully flow from the valve vent outlet, and resulting in repeated impact of the ball float with the valve adapter. In time, this indefinite oscillation of the ball float can result in fracturing the surface of the ball float, and an inability of the ball float to seal against the planar valve seat member. During the malfunction, water typically escapes at a faster rate than a normal drain can accommodate, allowing water to overflow onto the aircraft galley carpet, and wasting the limited amount of potable water available on the aircraft.
It would therefore be desirable to provide an aircraft water heating tank air vent valve that reduces the likelihood of such a malfunction and allows the vent ball to overcome such a malfunction event by changing the flow dynamics of the valve, so that the ball float can quickly be seated, by dampening the potential energy of rebounding of the ball float during any such oscillation that may occur, to quickly stop such oscillation, to minimize flow of water from the vent outlet, to allow the valve to function as intended, and to minimize possible damage to the ball float. The present invention meets these and other needs.